Flameproof cellulose organic acid ester fibers and process for their preparation



ioe latl EeQBEMHiE FLAMEPROOF CELLULOSE ORGANIC ACID ESTER FIBERS AND PROCESS FOR THEIR PREPARATION Robert C. Harrington, Jr., and James L. Smith, Kingsport, Tenn., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Application December 12, 1957 Serial No. 702,263

13 Claims. (Cl. 106-15) This invention relates to flame resistant compositions of matter and methods for their preparation. More particularly, this invention relates to flame resistant cellulose organic acid ester compositions, especially cellulose acetate, containing certain amphoteric metal chloroorganic phosphates. The present invention also relates to shaped articles such as synthetic filaments, fibers, and textile goods made from or containing such novel flame resistant compositions as well as to methods for incorporating the amphoteric metal chloro-organic phosphates therein.

Heretofore, several eflective fire retardants were available for use with cellulose acetate, the organic types such as tricresyl phosphate and tris(B-ch1oroethyl) phosphate must be employed at a relatively high concentration level (7-15 to be really effective. Also, these types of compounds are very easily removed by scouring and dry cleaning and thus, their nonflammable properties are lost to the fiber. It is also well known that the inclusion of high percentages of extraneous matter and plasticizers, in particular, lowers the physical properties of the fiber to a point where'their use is quite limited. These factors, together with the high level of toxicity found in such compounds as tris([3-chloroethyl) phosphate, serve to restrict their use for many purposes.

An object of the present invention is to provide cellulose organic acid ester compositions, fibers, filaments and fabrics which have good flame proofing characteristics. A further object of this invention is to provide cellulose acetate compositions and articles made therefrom which are flame resistant. Another object is to render cellulose acetate yarn nonfiammable without appreciably altering the physical characteristics and properties of the yarn such as strength, stretch, luster, and hand. A further object is to produce a nonflamrnable acetate which will retain nonflammable characteristics through several launderings after long wear or use. A still further object is to produce a nonflammable cellulose acetate fiber with a low order of toxicity. Other objects will appear hereinafter.

In accordance with the present invention, we have found that cellulose organic acid ester compositions and filaments made therefrom may be made inflammable by incorporating therein a small amount of an amphoteric metal salt of bis(/8-chloroethyl) phosphate. We have found that the amphoteric metal salts of aluminum, titanium, and tin bis(fi-chloroethyl) phosphate are effective as fire retardants for cellulose esters, particularly cellulose acetate in the range of 0.5 to 5.0% based on the weight of the cellulose ester. We have found that 1% of any of these salts is satisfactory in most instances. These salts are insoluble white solids and not only have a lower order of toxicity, but are much more difficult to remove from a fiber by scouring or dry cleaning. If fibers are to be made, these salts may be advantageously incorporated homogeneously into the cellulose ester spinning solution and the filaments are dry spun from this solution by the well-known dry spinning process. The

2,933,402 Patented Apr. 19, 1960 yarns and fabrics made from these filaments have excellent flame proofing properties.

The practice of the present invention is illustrated in the following examples:

Example 1 Aluminum bis (,e-chloroethyl) phosphate was prepared by refluxing a mixture of 1 mole (133 grams) of anhydrous aluminum chloride with 3 moles (852 grams) of tris(B-chloroethyl) phosphate in an inert solvent. The aluminum bis (B-chloroethyl) phosphate is recovered, washed with water, and dried. It may be ball milled in a suitable solvent such as acetone for inclusion in cellulose acetate, or other cellulose ester dry spinning solutions.

Example 2 Titanium bis( 3-chloroethyl) phosphate was prepared by refluxing 1 mole (189.7 grams) of titanium tetrachloride with 4 moles (1136 grams) of tris( 3-chloroethyl) phosphate in an inert solvent. The titanium bis(B-chloroethyl) phosphate is recovered as a white solid after washing. It can then be ball milled in acetone until reduced in size suitable for addition to the selected cellulose ester spinning solution.

Example 3 Stannous bis(B-chloroethyl) phosphate was prepared by refluxing one mole (189.6 grams) of anhydrous stannous chloride with two moles (568 grams) tris(fl-chloroethyl) phosphate in an inert solvent. The stannous bis- (fl-chloroethyl) phosphate is collected and, after washing and ball milling is ready to be used as a fire retardant additive for cellulose esters such as cellulose acetate.

Example 4 Aluminum bis(fi-chloroethyl) phosphate was ball milled and added to an acetone spinning solution of cellulose acetate containing 27% acetate in an amount of 0.5% based on the weight of the ester. This solution was then spun into yarn by the well-known dry spinning process such as is described in H. G. Stone Patents 2,000,048 and 2,000,049. Skeins of yarn and fabrics made therefrom would not burn when exposed to a flame.

Example 5 Aluminum bis([3-chl0roethyl) phosphate was added to a cellulose acetate spinning solution containing 27% acetate in amount of 3% based on the weight of the ester and this solution was dry spun into yarn. This yarn would not burn when exposed to flame either in a skein or after it was made into a fabric. A similar yarn containing but 1% of this fire retardant likewise would not burn either in skein or fabric form.

Example 6 Titanium bis(B-chloroethyl) phosphate was added to a cellulose acetate spinning solution containing 27% acetate in the amount of 1% based on the weight of the ester, and which was then spun into yarn. This yarn would not burn either in skein or fabric form when exposed to a flame.

Example 7 Stannous bis(,6-chloroethyl) phosphate was added to a cellulose acetate solution containing 27% acetate in the amount of 1% based on the weight of the ester. This solution was dry spun into yarn and it would not burn either in skein or fabric form.

Examples 4 to 7 were repeated using respectively as the cellulose ester component of the composition, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate phthalate, and

3 similar fire protection was imparted to the yarn and fabrics made therefrom.

These yarns are readily dyeable with the usual acetate dyes and the presence of the fire retardants does not affect dyeability or color fastness. Neither does the presence of these fire retardants in the yarn cause toxicity problems or adverse eflect on the physical properties of the fibers.

Example 8 A dry spinning solution consisting of 29.0% cellulose acetate, 1% aluminum bisflfi-chloroethyl) phosphate, 1.75% water and 68.25% acetone was spun into substantially perfect U-shaped cross-section filaments of a denier of 21.4 using the apparatus and general operation described in connection with Fig. 1 of Smith et al. patent application S.N. 675,392, filed July 31, 1957, entitled Process and Apparatus for Dry Spinning Synthetic Filaments and Fibers and Products Produced Therefrom. A pile rug was made from yarn comprising a multiplicity of these filaments. The rug was flame tested and found suitable for general use in a home from the standpoint of nonflammability.

We claim:

1. A flame resisting composition essentially consisting of a cellulose organic acid ester selected from the group consisting of cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate and cellulose acetate phthalate and as a flameproofing component from 0.5 to 5.0% by weight of the ester of an amphoteric metal salt of bis(fi-chloroethyl) phosphate, the amphoteric metal being one selected from the group consisting of aluminum, tin and titanium.

2. A flame resisting composition essentially consisting of a cellulose organic acid ester selected from the group consisting of cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate and cellulose acetate phthalate and as a flameproofing component 1% by weight of the ester of aluminum bis(fichloroethyl) phosphate.

3. A flame resisting composition essentially consisting of a cellulose organic acid ester selected from the group consisting of cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate and cellulose acetate phthalate and as a flameproofing component 1% by weight of the ester of titanium bis(B- chloroethyl) phosphate.

4. A flame resisting composition essentially consisting of a cellulose organic acid ester selected from the group consisting of cellulose acetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate and cellulose acetate phthalate and as a flameproofing component 1% by weight of the ester of stannous bis(,8- chloroethyl) phosphate.

5. A flame resisting composition essentially consisting of cellulose acetate and as a flameproofing component from 0.5 to 5.0% by weight of the acetate of aluminum bis(,8-chloroethyl) phosphate.

6. A flame resisting composition essentially consisting of cellulose acetate and as a flameproofing component from 0.5 to 5.0% by weight of the acetate of titanium bisUS-chloroethyl) phosphate.

7. A flame resisting composition essentially consisting of cellulose acetate and as a fiameproofing component from 0.5 to 5.0% by weight of the acetate of stannous bis(,6-chloroethyl) phosphate.

8. Cellulose acetate fibers containing by weight 0.5 to 5.0% of an amphoteric metal salt of bis({3-chloroethyl) phosphate, the amphoteric metal being one selected from the group consisting of aluminum, tin and titanium.

9. Cellulose acetate fibers containing by weight 1% of aluminum bis({3-chloroethyl) phosphate.

10. Cellulose acetate fibers containing by weight 1% of titanium bis(fi chloroethyl) phosphate.

11. Cellulose acetate fibers containing by weight 1% of stannous bis(,8-chloroethyl) phosphate.

12. A fabric containing as fireproofing elements cellulose acetate yarns containing 0.5 to 5.0% by weight of the acetate of an amphoteric metal salt of bisQSi-chloroethyl) phosphate, the amphoteric meta] being one selected from the group consisting of aluminum, tin, and titanium.

13. A pile rug comprising cellulose acetate yarns containing 1% of aluminum bis({3-chloroethyl) phosphate.

References Cited in the file of this patent UNITED STATES PATENTS 2,052,558 Dreyfus Sept. 1, 1936 2,202,124 Tattersall May 28, 1940 2,330,251 Taylor et al. Sept. 28, 1943 2,330,253 Whitehead Sept. 28, 1943 2,330,254 Whitehead Sept. 28, 1943 2,618,568 Meyer et al. Nov. 18, 1952 OTHER REFERENCES American Ink Maker, Flame Resistant Plasticizer, December 1949, page 49.

Patent should read as corrected below.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,933,402 April 19, 1960 Robert C, Harrington, Jr. et a1.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Column 1, line 57 for "inflammable" read nonflammable Signed and sealed this 22nd day of November 1960. Q

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attaining Officer Commissioner of Patents 

1. A FLAME RESISTING COMPOSITION ESSENTIALLY CONSISTING OF A CELLULOSE ORGANIC ACID ESTER SELECTED FROM THE GROUP CONSISTING OF CELLULOSE ACETATE, CELLULOSE PROPIONATE, CELLULOSE ACETATE PROPIONATE, CELLULOSE ACETATE BUTYRATE AND CELLULOSE ACETATE PHTHALATE AND AS A FLAMEPROOFING COMPONENT FROM 0.5 TO 5.0% BY WEIGHT OF THE ESTER OF AN AMPHOTERIC METAL SALT OF BIS(B-CHLOROETHYL) PHOSPHATE, THE AMPHOTERIC METAL BEING ONE SELECTED FROM THE GROUP CONSISTING OF ALUMINUM, TIN AND TITANIUM. 